The objective of the research is to prepare derivatives of bleomycin from the active ester of bleomycin and a DTPA like molecule. Because bleomycin directly labeled with 57Co has ideal biological properties but poor nuclear characteristics, other radionuclides have been directly labeled to bleomycin. Since none of these have been as stable in vitro or in vivo as 57Co, it is worthwhile to prepare derivatives of bleomycin in order to bind a metallic radionuclide to bleomycin. DTPA has been directly reacted with the alpha amino group of bleomycin and the 169Yb derivative shows high tumor to blood ratios. In addition a new DTPA like molecule which will readily react with the active ester of bleomycin has been prepared. A reversed phase liquid chromatographic system has been developed which facilitate the separation of bleomycin fractions and bleomycin derivatives. BIBLIOGRAPHIC REFERENCES: Rzeszotarski WJ, Eckelman WC and Reba RC. The Reversed Phase High Pressure Liquid Chromatography of Bleomycin. J. Chromat. 124: 88-91, 1976.